One glance at Josie Maran and you’re left with the image of a tall, thin, athletic woman. But looks can be decieving. On Dancing with the Stars, Josie’s partner, Alec Mazo, called her “deceptively unfit,” and a nation of viewers simply couldn’t understand that although she was skinny, she wasn’t necessarily in top shape.

Fitness Magazine set out to change that with a 30-day fitness makeover. With the help of a trainer and a nutritionist, Josie, 29, was quickly on her way toward healthier living. “Before, it was crash and burn, high and low,” she tells the magazine, on stands January 15. “It’s not like I had no energy, it just was really inconsistent. Now, I feel very even throughout the day.”

Fitness guru Michelle Austin and nutritionist Ashley Koff, who had Josie working out 30 to 40 minutes every other day and eating every three hours, helped Josie strive for her goal of getting toned without dropping weight. The results, Josie says, were amazing.“I still wear the same size jeans!” she jokes. Three weeks into her makeover, Josie reveals that she can feel her “pelvic wall getting really strong. I feel stronger in my core than I ever have, especially since I had my daughter, Rumi Joon, 18 months ago.”

The Sports Illustrated swimsuit model and actress adds that despite her profession—or perhaps because of it—she ultimately underwent the makeover for herself. “In my business, if you look good, no one is going to be checking up on whether you work out,” she says. “So it’s up to me.”